| // Copyright 2020 The Pigweed Authors |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); you may not |
| // use this file except in compliance with the License. You may obtain a copy of |
| // the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| // License for the specific language governing permissions and limitations under |
| // the License. |
| #pragma once |
| |
| #include <cstddef> |
| |
| #include "pw_bytes/span.h" |
| #include "pw_polyfill/language_feature_macros.h" |
| #include "pw_span/span.h" |
| #include "pw_status/status.h" |
| #include "pw_status/status_with_size.h" |
| #include "pw_stream/stream.h" |
| |
| namespace pw::stream { |
| |
| // Stream that silently drops written data and returns nothing on reads, similar |
| // to /dev/null. |
| class NullStream final : public SeekableReaderWriter { |
| public: |
| // Gives access to a global NullStream instance. It is not necessary to have |
| // multiple NullStream instances since they have no state and do nothing. |
| static NullStream& Instance() { |
| PW_CONSTINIT static NullStream stream; |
| return stream; |
| } |
| |
| private: |
| Status DoWrite(ConstByteSpan) final { return OkStatus(); } |
| StatusWithSize DoRead(ByteSpan) final { return StatusWithSize::OutOfRange(); } |
| Status DoSeek(ptrdiff_t, Whence) final { return OkStatus(); } |
| }; |
| |
| } // namespace pw::stream |